Expansile, intraocular lenses have been designed to take advantage of the swelling and expansion upon hydration of hydrophilic materials. This permit the lenses prior to implantation to be smaller than other implants, or previously non-expansile artificial lenses since the expansile lenses are hydrated by the fluid present in the normal eye and expand to the predetermined, desired, optically correct size. Intraocular lenses are composed of a dry, solid hydrophilic material capable of expansion by absorbing the fluid present in the eye by hydration to a final diameter up from about 5 millimeters to about 14 millimeters to reach the predetermined, optically correct lens for the particular patient. These dehydrated lenses have a minimum diameter of about 3 millimeters and an maximum of about 5 millimeters in the dry state, which, of course, is less than the diameter of existing non-expansile lenses. This has permitted the implantation of intraocular lenses through an incision corresponding to less than 5 millimeters diameter compared to the non-expansile, intraocular lenses which require an incision of at least 6 millimeters and up to 10 millimeters.
Despite the above-mentioned reduction in lens size, the need for still smaller intraocular lenses is recognized. Wound size has always been extremely important in ophthalmology for the size of the wound determines the amount of the astigmatism and the speed of healing in the eye. This need for smaller size intraocular lenses has been at least partially fulfilled by reducing the cross-sectional diameter of the intraocular lenses by compressing the lens during the dehydration phase as pointed out in my recently issued U.S. Pat. No. 4,813,954. Up till the present time, intraocular lenses of about 3.2 millimeters in size in the totally dehydrated, untouched state have been made. Such lenses then swell to approximately 5.8 millimeters. Because of the limitation in the plastic material employed, limitation in the insertion size seems to be somewhere around 3 millimeters. By the use of the apparatus of my invention, the incision size has been reduced below 3.2 millimeters. The apparatus functions by compressing and deforming the hydrated intraocular lens as it is dried under a constant force, the deformation being maintained as the lens becomes dehydrated.
As is the case with all lenses, expansile intraocular lenses being no exception, they must be oriented along the visual axis within the eye. The visual axis is an imaginary line which passes actually through the center of the lens and extends through the pupil and cornea. The lens must be centrally oriented along this axis in the path of the light to the retina. The curved front and back surfaces of the lens or disc must be precisioned on the same axis to provide an optically correct orientation. To provide such orientation haptic loops are employed. Their purpose is to anchor the lens in a central position along the visual axis. The curved portion of the loops contact the chamber walls and hold the lens in place. In designing an apparatus to fabricate intraocular lenses for insertion in minimal incisions consideration must be given to placement of the haptic loops. They must maintain their orientation during any deformation of the optic.